I. Field of the Invention
The present invention relates to a method and device for cleaning equipment in the graphic arts industry by airblasting with solid particles of carbon dioxide. More particularly, the present invention relates to cleaning printing press components by airblasting with particles of carbon dioxide.
II. Discussion of References
Devices employed in the printing industry become contaminated with debris such as ink and lint. This problem occurs whether the printing is on paper or fabrics. The debris also forms, to varying degrees, on all kinds of printing equipment. For example, offset printing has become the predominant printing method in the newspaper publishing industry. Offset printing presses typically employ a blanket cylinder. Blanket cylinder is a rubber cylinder or a rubber-covered cylinder, for the purposes of receiving inked images from a printing plate. The inked images are then offset onto paper paths between the blanket cylinders or an impression cylinder. Continuous printing is made possible by wrapping a printing plate or a plurality of printing plates around the surface of a plate cylinder designed for rotation in contact with the blanket cylinder. In operating blanket-to-blanket presses, a web of paper passes between two blanket cylinders mounted such that one blanket cylinder serves as an impression cylinder for the other. This results in "perfecting" which is simultaneous printing on both sides of the web of paper.
Continuous offset printing is adversely affected by dust and lint from the web of paper which tend to accumulate on the blanket cylinder(s). This dust and lint reduces the quality of the printed product. The accumulation of dust, lint, or ink on a blanket cylinder thus presents a serious annoyance and necessitates undesirable down-time for cleaning. The problem is especially acute in the newspaper industry, when, in response to the rising cost of newsprint stock, less expensive grades of paper having higher lint content often are substituted for more expensive grades.
The problem of collection of debris such as ink, dust and lint on printing devices is not limited to offset printing. It occurs in press equipment in general. For example, it occurs on Anilox Rollers, Flexo Plate Cylinders and Plates, pipe rollers in newspaper presses, metal decorating press blanket cylinders, rollers, and impression cylinders, Gravure press cylinders and rollers, Flexo press cylinders or rollers, and textile printing plates, blankets and rollers. The problem of cleaning printing equipment is well known as indicated by prior efforts for printing equipment cleaner devices.
In some types of printing, sheets are cut and stacked prior to printing. The sheets are prevented from sticking by application of a dusty material such as corn starch. Use of corn starch laden sheets provides another source of debris.
U.S. Pat. No. 4,344,361 to MacPhee et al. discloses an automatic blanket cylinder cleaner having a cleaner fabric adapter to contact a blanket cylinder. A cleaning roll supply roller provides cloth for cloth take-up roll. Positioned between these rolls is a water solvent dispensing tube, a solvent dispensing tube and an inflatable and deflatable mechanical loosening means which is adapted to move the cleaning fabric into and out of the contact with the blanket cylinder. This patent is incorporated by reference.
Devices employing carbon dioxide for sandblasting are disclosed by U.S. Pat. No. 4,038,786 to Fong and U.S. Pat. No. 4,389,820 to Fong et al. Both of these patents are incorporated herein by reference.
However, these patents do not disclose employing particles of carbon dioxide or other sublimable particles for use in cleaning printing devices.